This invention relates to fire retardant, curable, ethylenically unsaturated compositions containing ester linkages. This invention also relates to a process for rendering fire retardant a curable, ethylenically unsaturated composition containing ester linkages.
Fire retardant, curable, ethylenically unsaturated compositions are known from, inter alia, U.S. Pat. No. 4,013,815. The compositions contain unsaturated polyester resin which is cured by copolymerization of an unsaturated polyester and an ethylenically unsaturated monomer. Most iron compounds mentioned in the U.S. patent, such as ferric acetate, ferric formate, and ferrous tartrate, when added in an amount of 0.55 to about 50 percent, by weight, based on unsaturated polyester, are found to be fire retardant only to such a degree that at least 4.4 percent, by weight, of halogen, based on the amount of cured polyester resin must still be present in order for the compositions to be effectively fire retardant.
In view of the increasingly stringent demands made on industrial products, especially with respect to their effect on the environment, there is a very great need for unsaturated polyester resin compositions which have been made fire retardant without the inclusion of halogen compounds.
In view of the foregoing, an object of this invention is to provide curable, ethylenically unsaturated compositions containing ester linkages which have been made sufficiently fire retardant without the necessity for including a halogen compound.